Not applicable
1. Field of Invention
This invention relates to devices for sensing the location of projectiles as they hit a target, specifically to dartboards that automatically sense the location of each dart as it hits the dartboard, scoring the dart instantaneously.
2. Description of Prior Art
Traditional dartboards are made of tightly packed fibers for use with xe2x80x9csteel-tippedxe2x80x9d darts. These boards have existed for some time, however players must score their own darts. In order to make a dartboard that automatically scores the darts, an electronic board was invented that is made of plastic and has many small holes in it for use with plastic-tipped darts. When a dart strikes a particular section of the board the section is depressed sending an electronic signal that counts the dart. While electronic dartboards for plastic or xe2x80x9csoft-tippedxe2x80x9d darts have become popular in many parts of the country, in part because they are self-scoring, they do not have the same appeal to many people as traditional steel-tipped darts.
These two types of darts/dartboards, namely steel-tip and soft-tip, are not interchangeable. Steel-tipped darts are typically heavier, and the tip has a larger diameter than soft-tipped darts. The larger diameter and greater mass of the steel-tipped darts mean that they cannot be used with the plastic electronic boards as this would permanently damage the board.
The disadvantage of the electronic soft-tipped dartboards is not in their function, but simply that it is not the same game as the traditional steel-tipped darts. One disadvantage of soft-tipped darts is demonstrated by the fact that the darts are lighter and do not have the same feel as the steel-tipped darts, also the plastic tips often bend and break and constantly need to be replaced. The disadvantage of the traditional steel-tipped darts is that they do not automatically score the darts.
Several automatic-scoring dartboards have been developed for use with steel-tipped darts. U.S. Pat. No. 6,089,571 to Cho (2000) and U.S. Pat. No. 6,215,390 to Lin (2001) are similar in describing a relatively complex design in which separate sisal blocks are depressed when a dart strikes the dartboard. The momentum from the dart presses the sisal block which activates a touch switch completing an electrical circuit, and identifying the section of the board that was struck by the dart. The disadvantages of this design are numerous. The board itself is redesigned and thus more costly to manufacture. Changing the board so that separate sections of the board can be depressed changes the game significantly. Darts that would normally have remained in the board, are now more likely to fall out.
There are several more devices that consist of separate blocks or sections that are depressed when a dart or projectile strikes that particular section. One of these is described in U.S. Pat. No. 5,613,685 by Stewart et al. (1997). The dartboard is made from conductive blocks that are depressed upon impact and thus complete a circuit. The function of this device is similar to the one described by Lin above, and also suffers from the same disadvantages. Similar devices are described by Cho and Lin in U.S. Pat. No. 6,116,607 (2000), and by Lu et al. in U.S. Pat. No. 6,047,968 (2000). These devices suffer from the disadvantages of changing the game significantly, and increasing costs. Another disadvantage of these boards is that they do not register any quantity to the force of impact.
Another system for locating the presence of a dart in a dartboard detects a change in electrical conductivity. U.S. Pat. No. 6,155,570 by Allison (2000) describes a device in which the bristle fibers of the dartboard are coated with a conductive material such as graphite. The major disadvantage of this dartboard is that the graphite comes off on the darts and gets on the hands of the players.
There is one automatic electronic scoring device for steel-tipped darts that is currently on the market. This device scans the surface of the dartboard with lasers and senses the location of the darts by detecting the light reflected off the darts. While this device functions fairly accurately, its major disadvantage is its high cost. The current retail price for the device is approximately 20 times the price of a standard non-scoring bristle dartboard. The accuracy has been reported to be on the order of 99%.
There have also been several projectile-locating devices developed that may or may not be used with darts. U.S. Pat. No. 5,669,608 to Thomson et al. (1997) discloses a complex multi-layer device in which the projectile must penetrate several layers of the detector. When a projectile breaks the lamina-type parallel planes, the impact location is detected as a change in voltage. This has the obvious disadvantage that the detector is penetrated and after much use would cease to function properly.
A device by Kustanovich in U.S. Pat. No. 4,659,090 (1987) detects impact locations in a relatively complex multi-layer system. While the detection system involves the measurement of changes in impedance when a force impacts a target, a prohibitively large number of layers are involved. For example, the preferred embodiment of the invention requires 11 layers to provide impact locations for just 4 sections.
Another device detects the location and speed of a projectile as it strikes a target based on the acoustic shockwaves produced upon impact. This design is described in U.S. Pat. No. 5,447,315 by Perkins (1995). With the sound detectors located on the periphery, the location of the impact is determined by the exact time that each detector senses the acoustic shockwaves. The speed of the projectile is estimated by the magnitude of the shockwaves. The device requires a special layer in which the projectiles strike, the layer designed to produce a loud sound with the impact. This device is not practical for use with the standard bristle dartboard since very little sound is produced with the impact of a dart in the sisal fibers.
There are several disadvantages of regular traditional non-scoring bristle dartboards. One disadvantage is that they cannot interface with a computer. Incorporating a computer interface allows many more games to be played, the most prominent of which is the ability to play through the Internet with a player at a different location.
Another disadvantage of current dartboards as well as the devices described above (except Kustanovich, 1987, and Perkins, 1995) is that they do not provide any measure of the force of impact of the dart. Playing darts well requires the ability of the player to throw each dart consistently with very precise motions. One measure of this precision is the force of the impact to the dartboard. By showing the player the force of each dart upon impact it will be possible for the player to develop a consistent and accurate throw. Currently there are no dartboards that quantify the force of impact of the dart to the dartboard.
While there are working devices which can detect the location of darts as they hit the dartboard, all such devices heretofore known suffer from a number of disadvantages:
a) currently there is are few working auto-scoring electronic dartboards made from traditional sisal fibers available to consumers, and these do not function with 100% accuracy;
b) the electronic dartboards currently being made use lighter darts with plastic tips that often break and have to be replaced. These darts do not have the same feel as the original, traditional darts;
c) although working devices for detection of all types of darts have been made, they are complex and expensive to manufacture, and they change the game significantly;
d) with traditional bristle dartboards, players must know all the games themselves. The board itself does not offer and suggest different dart games to play;
e) currently there are no traditional dartboards that allow players to play the game of darts through an internet connection, allowing players from virtually anywhere in the world to play against each other;
f) current dartboards do not quantify the force of impact of the darts.
In accordance with the present invention, an electronic device for detecting projectile impact locations comprises an impact-absorbing front layer that absorbs a large part of the initial force of impact. The force of impact is transferred to a sensor that sends the impact magnitude and location data in the form of a standard electronic signal (such as a small change in impedance) to standard circuitry and a display or computer-screen.
Objects and Advantages
Accordingly, several objects and advantages of my invention are:
a) to provide an electronic traditional sisal fiber dartboard that automatically senses and records the location of each dart as it strikes the dartboard, with such a device being  greater than 99% accurate and relatively inexpensive;
b) to provide a method of scoring darts that utilizes the traditional steel-tipped darts with their superior quality and feel; the steel-tips being permanent, and do not need constant replacing;
c) to provide a method of automatically scoring the game of traditional steel-tip darts that utilizes a detection technology that is inherently simple and inexpensive, and will not significantly change the game itself;
d) to provide an electronic bristle dartboard that has a wide variety of pre-programmed dart throwing games;
e) to provide an electronic bristle dartboard that allows dart players to play through the internet;
f) to provide an electronic bristle dartboard that provides a display of the impact force of each dart thrown.
Further objects and advantages are to provide a bristle dartboard that does not require the players to keep score of their game. In league play this will speed things up considerably and may even allow more games to be played in a given match. This electronic bristle dartboard also will allow the use of the heavier, traditional steel-tip darts, and will not change the game of darts in any way except to free the players from the need to keep score of their darts. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.